Diseases of Vegetable, Ornamental and Spice Crops

QUESTIONS

Q.No. 1. Tick the correct answer
1. The perfect stage of Colletotrichum orbiculare is:

a) Glomerella lagenarium b) Thanatephorus cucumeris c) Diaporthe vexans d) Diplocarpon rosae

2. Pseudoperonospora cubensis overwinters in the soil in the form of :

a) Sclerotia b) Oospore c) Conidia d) Chlamydospore

3. Fusarium oxysporum f.sp. cucumerinum overwinters as:

a) Sclerotia b) Oospore c) Conidia d) Chlamydospore

4. Favourable conditions for downy mildew development are:

a) High rainfall coupled with high soil temperature
b) High rainfall coupled with moderate temperature
c) High rainfall and coupled with 20to 22o C temperature
d) High rainfall and soil moisture coupled with low temperature

5. Anthracnose of cucurbits is caused by :

a) Macrophomina phaseolina b) Rhizoctonia solani
c) Colletotrichum orbiculare d) Sclerotinia sclerotiorum

6. Most striking symptoms of anthracnose appear on fruits as:

a) Dark brown and smooth b) Roughly circular and sunken
c) Light brown and smooth d) Brown and sunken

7. Brown coloured powdery spots develop due to the infection of:

a) Erysiphe cichoracearum b) Sphaerotheca fuliginea c) Sphaerotheca pannosa d) Erysiphe polygoni

8. Optimum temperature for anthracnose is :

a) 10-15o C b) 15-20o C c) 22-27o C d) 25-30o C

9. Cucumber mosaic virus is transmitted by:

a) Aphid b) Whitefly c) Thrips d) Jassid

10. Angular leaf spot is caused by:

a) Fungus b) Bacteria c) Virus d) Nematode

Answers

1.a 2 b 3 d 4 c 5 c 6 b 7 b 8 c 9 a 10 b

Q.No. 2. Fill in the blanks:

1. Anthracnose of cucurbits pathogen perpetuate in the form of----------------------- and in--------------------------------.
2. Bacterial wilt is caused by-------------------------------------.
3. In field the spread of anthracnose can be limited by the sprays of ---------------------- or ------------------------.
4. Sporangia of Pseudoperonospora cubensis germinate by----------------------
5. Optimum temperature for sporulation, spore germination and symptom development of downy mildew -----------------------^oC.
6. Powdery mildew of cucurbits overwinters in the form of -------------------- and ---------------------.
7. The optimum temperature for powdery mildew development is----------------------------.
8.. Cucumber mosaic virus belongs to the genus -----------------------.
9. Angular leaf spot is more serious in temperature range of ----------- to ----------.
10. Fibrosin bodies are present in the conidia of -------------------------------------.

Answers:

1. Seed and soil 2. Erwinia tracheiphila 3. Mancozeb, carbendazim 4. Zoospores 5. 20-22oC 6. Cleistothecia, conidia 7. 25o C 8. Cucumovirus 9. 20, 24o C 10. Sphaerotheca fuliginea

Subjective type questions:

1. Write down the causal organism and characteristic symptoms of following diseases:

a. Downy mildew
b. Angular leaf spot
c. Cucumber mosaic
d. Powdery mildew

2. Write down the management practices for the following diseases:

a. Anthracnose
b. Downy mildew
c. Cucumber common mosaic

3. Write down the disease cycle and epidemiology of following disease:

a) Angular leaf spot
b) Anthracnose
c) Downy mildew
d) Powdery mildew